#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int m = 20;
	int count = 0;
	while (m)
	{
		m--;
		count++;
		if (count % 2 == 0)
		{
			count++;
		}
	}
	printf("%d", count);
	return 0;
}